Polishing apparatus



1 n '25, 1963 R. F. PENDERGAST 3, 5

POLISHING APPARATUS ru Qct; 2. 1961 e Sheets-Sheet 1 IN VEN TOR. Reyna; F. Puma-264s? BYQMM June 25, 1963 R. F. PENDERGAST POL'ISHING APPARATUS Filed Oct. 2, 1961 s Shets-Sheet. 2

INVENTOR. Earn qua F. PEA/08261987 drrmwvs FIE. E

June 25, 1963 R. F. PENDERGAST 3,

POLISHING APPARATUS Filed Oct. 2, 1961 6 Sheets-Sheet 3 FIG. 2

INVENTOR. Ear/ram: F. PMDERG-JS? BY M Jrrazvsrs June 25, 1963 R. F. PENDERGAST 3,094,815

POLISHING APPARATUS .-Filed Oct. 2, 1961 I 6 Sheets-snag: 4

B (2% w M FIG. 5

Filed Oct- 2. 1961 Jun 25, 1963 R. F. PENDERGAST POLISHING APPARATUS 6 Sheets r-Sheet 5 INVENTOR. RA YMOIVD FPFMflE/QGJST 5 United States Patent 3,094,815 POLISHING APPARATUS Raymond F. Pendergast, Grey Eagle, Minn. Filed Oct. 2, 1961, Ser. No. 146,034 10 Claims. (Cl. 51-60) This invention relates to an improvement in a polishing apparatus and particularly in one for various types of surface polishing of articles particularly of a size which may be belt fed into contact with the polishing mechanism.

It is an object of this invention to provide a polishing apparatus arranged and constructed for longitudinal as well as transverse polishing action for substantial improvement in polishing effect upon the surface of a work piece.

It is a further object of this invention to provide a polishing apparatus having a movable belt having automatic reversible action passing over a polishing head with said polishing head being adapted to reciprocate longitudinally and transversely in continuous action.

It is also an object of this invention to provide a polishing apparatus comprising a central supporting structure carrying the polishing mechanism in suspended condition for precise adjustment of said mechanism.

It is another object of this invention to provide a polishing apparatus comprising a plurality of polishing heads, with said polishing heads having coordinated action.

These and other objects and advantages of the invention will be fully set forth in the following description made in connection with the accompanying drawings in ,which like reference characters refer to similar parts throughout the several views and in which:

FIG. 1 is a view of applicants apparatus in side elevation;

FIG. 2 is a top plan view of applicants apparatus;

FIG. 3 is a fragmentary view in horizontal section taken on line 3-3 of FIG. 1, as indicated by the arrows;

FIG. 4 is a view in vertical section taken on line 4-4 of FIG. 1, as indicated by the arrows;

FIG. 5 is a view in side elevation of a modified structure with some portions being shown in dotted line;

FIG. 6 is a view in horizontal section on line 66 of FIG. 5 as indicated by the arrows;

'FIG. 7 is a broken view in side elevation with some parts being shown in dotted line and some parts in section of a modification of a portion of applicants device as shown in FIGS. 1-4;

FIG. 8 is a view in horizontal section taken on line 8-8 of FIG. 7, as indicated by the arrows; and

FIG. 9 is a view in vertical section taken on line 9--9 of FIG. 7, as indicated by the arrows.

With reference to the drawings, applicants apparatus comprises an upstanding standard or supporting frame structure 10 indicating in horizontal section the form of a rectangular figure and having legs 11-14 and a pair of vertically disposed opposing parallel plate sides 16 and 17 at the upper portion thereof. Upstanding centrally longitudinally of said standard 10 and extending transversely thereacross is a second upstanding standard 20 having supporting legs 2225 respectively having outturned bottom flange portions secured to the upper edge portions of said side plates 16 and 17 by bolts 18 and in turn supporting a top or cover plate 27 therebetween.

Said standard 10 has an extension to the right thereof, as viewed in FIGS. 1 and 2, comprising legs 30 and 31 and having side frame members 32 and 33 extending between and secured to legs 12 and 30 and to legs 13 and 31 with a plate member 35 being supported thereon and here indicated as only partially overlying the same and being somewhat spaced from the adjacent end of said standard 10.

3,094,815 Patented June 25, 1963 Depending from said plate 27 is a polishing head structure 37 shown here as being substantially parallelepiped in form having sides 38 and 39 and ends 40 and 41, with said ends being shown having greater thickness than said sides, and secured to the lower end portions of said ends and sides in a suitable manner is a bottom plate portion 42 forming a platen which is here shown having a somewhat greater length than the width between the sides 38 and 39. Spaced transversely of the upper end portions of said ends 40 and 41 respectively are inwardly extending shoulders 40a and 41a, as indicated in FIGS. 2 and 4, with said shoulders having journaled therein the lower portions of jack screws 45-48, with said jack screw 48 having a handle 48a. Said jack screws extend upwardly through said plate 27 through apertures therein, and secured to said plate 27 in alignment with said apertures are nuts 50 through which said jack screws are threaded. Mounted on the lower shank portions of each of said jack screws and secured thereto are sprocket gears 52 merely indicated in FIG. 2, and passing about said gears is a sprocket chain 53. Thus said jack screw assembly holds said polishing head in a vertically adjustable suspended position with the rotation of said jack screws by operation of the crank or handle 48a.

Formed in each of said ends 40 and 41 are two transversely spaced vertically extending grooves 40b'40b and 41b-41b respectively. Formed in each of said side plates 16 and 17 vertically spaced are parallel horizontally extending grooves 16a16a and 17a17a respectively.

cooperatively associating said grooves 40b40b and 16a16a is a rectangular plate member 55 having vertically .spaced horizontal outwardly extending slides or runners 55a-55a at one side thereof to be disposed in said grooves 16a-16a. At the other side of said plate members are longitudinally spaced vertically disposed outwardly extending slides or runners 55b-55b disposable in said grooves 40b40b.

In association with said end plate 17 is a rectangular plate member 57 identical to said plate 55 and having at the outer side thereof horizontal slides or runners 57a57.a slidable in said grooves 17a17a and having at its inner side vertical slides or runners 57b-57b slidable in said grooves 41b41b. Said grooves 40b-40b and 41b41b are of somewhat greater depth than the inward extension of said slides or runners 55b--55b and 57b-57 b respectively. Further the distance between the remote surfaces of said plates 55 and 57 as positioned in FIG. 4 will be somewhat less than the distance between the facing surfaces of said ends 16 and 17 to provide for some endwise movement or play of said polishing head 37.

Extending outwardly oppositely of said polishing head 37 at upwardly inclined angles and respectively integral with the sides 38 and '39 thereof are pairs of spaced arms 60 and 61 carrying at their free ends respectively spools or rollers 64 and 65 having respectively secured thereto the free ends of a polishing belt or strip 67 of suitable composition for polishing purposes. While said belt may be variously composed, it is here indicated as being a type to use a polishing compound in connection therewith. Said belt will be initially carried by one roller, such as roller 64 in FIG. 1, with a free end portion being disposed over the outer side of the. platen 42 and secured to the other roller or' roller 65, as in FIG. 1. As will be explained, said polishing belt is wound from one roller onto the other and reversed.

Said rollers are respectively mounted onto shafts 70 and 71 which are journaled respectively between said spaced arms 60 and 61 adjacent the free ends thereof. Secured to said shaft 70 is a pulley 75 and to said shaft 71 a pulley J76. Carried at an outer end of, shaft 70 and in engagement with the adjacent side of said arm 60 is an adjustable brake or drag mechanism 72 of a common design to prevent said shaft 70 from running free and to keep the polishing belt taut. A similar brake mechanism 73 iscarried adjacent one end of said shaft 71.

Mounted on said plate member 27 is a shaft structure 80' having pulleys 82" and 83 respectively mounted at the ends thereof. A belt '86 passes over said pulleys 7'5 and 82 and a belt -87 passes over said pulleys 76 and 83. Said shaft is mounted in bearing blocks 89 with one being adjacent either end thereof and being suitable secured to said plate 27. Mounted on said plate 27 in association with said shaft 80 are magnetic clutch members 94 and 55 of known construction and usage. Mounted centrally of said plate 27 is reversible electric motor 100 having its driving mechanism in operative association with a gear reduction box 102. Shaft portions 80a and 80b extend respectively from said gear box 102 to the driving portions of said clutch members 94 and 95. Extending from the driven sides of said clutch members 94 and 95 and extending outwardly thereof through said bearing block 89 and carrying said pulleys 82 and 83 respectively are shaft portions 80"c and 80d.

Mounted on the end portion of one of the arms 60 by a suitable bracket 107; as indicated in FIG. 1, is a commonly used type of a limit switch 105 having a roller equipped spring type actuating arm 105a constructed and arranged to bear against the polishing belt 67 accumulating on said roller 64. Mounted on the end portion of one ofthe arms 61 by a suitable bracket 108 is a second limit switch 106 having a spring pressed roller equipped actuating arm-106a bearing against the polishing belt about the roller 65.

Said limit switch 105 is in circuit with said clutch 94, as indicatedby conduits A, and said limit switch 106 is in circuit with clutch 95 by conduits B. Said limit switches respectively in circuit with said clutches are also in circuit in a conventional manner with said motor whereby when one limit switch is actuated by a suflicient accumulation of the polishing belt on its adjacent roller, its respective clutch will be disengaged; the motor will be reversed and the other of the clutches will be engaged to drive said'belt ina reverse direction. Thus the belt has continuous'movement; first in one direction and then in theother.v

Carried on said plate member 35 is an electric motor 110which' will be connected to-a source of power and in association therewith and adjacent thereto on said plate 35 is mounted a shaft 112 journaled in bearing brackets 113 and having a combination circular crank and pulley 115 secured to one end thereof havinga belt 116 passing over said pulley and a pulley 117 'carried on a shaft 120 which'is the driveshaft'of said motor 110. Secured to the other end of said shaft 112 is a second circular crank 122. Saidcranks respectively have studs 124 and 125 extending outwardly thereof in off-centered positions and respectivelyhavin'g crank arms 127 and 128 pivoted to said studs at one end of each of said cranks, with the other ends ofsaid cranks being respectively pivoted to studs 130 and 1'31- extending respectively outwardly'of said arms 61 adjacentthe lower portions thereof. Thus said cranks drivenbyi said motor'1'10 will reciprocate said arms 61 together with said polishin'g'head 37 longitudinally of said belt 67. Mounted on a. base portion 135 secured to the inner side of the platen'42 is a motor 137 for reciprocating said polishing head transversely of said'belt 67. This transverse reciprocation may be in various degrees. In the embodiment of the invitation here presented said reciprocation is rather rapid and only to a slight degree as far as travel. distance of said polishing head is concerned with said motor here being indicated as a vibrating motor which will be suitably connected to a'supply of power.

Positioned to be in an operating relation with said polishing head. 37 is an endless belt 140- passing over rollers 141 and 142 journaled in bearing brackets 143 and 144 respectively supported on spaced pairs of standards or legs l'46'and 147. Supporting the upper run of said belt 141! is an elongated plate member 150 which will extend transversely between said legs 11--14, 112-13, and 3tl'31, and will be secured to said legs and supported thereby as by bolts150 and suitable brackets 151 as indicated.

Shown on said belt 140 in FIG. 1 is a work piece 155.

Mounted at one side of said standard 10, as indicated in FIG. 1, is a hopper 157 secured by an angled bracket 158 and having a gravity fed tube 159 leading downwardly to a manifold or feeding head 160 suitably secured transversely of said standard and said polishing belt to feed a polishing compound onto work pieces carried on said belt and feeding the same just ahead of the point of engagement of said'work piece with said belt.

In operation, a work piece 155 will be placed on said endless belt 140 whereby it will be moved into operative association with the platen 42. Said platen 42 is adjustable as to height ordistance from the upper run of the belt 140 by means of the jack screws 4548 which will be rotated by means of the handle 48a. Polishing compound if desired is readily fed onto the Work piece and is gravity fed from the hopper 157 through the manifold 160 by means of a connecting tube 159-. The applicants apparatus has an improved and'unusually eflicient polishing action. The polishing belt 67 is in constant motion being wound from the roller 64 onto the roller 65, or in reverse direction as controlled by the limit switches and'106. At the same time the polishing head reciprocates longitudinally of the beltby means of the crank arms 127 and 128; being secured at one end of the cranks and 122 and being secured at their other ends to the arms 60 adjacent their base portions. Thus both the belt and the polishing head are reciprocating longitudinally of the belt and simultaneously the polishing belt 67 is in movement being drawn over the platen 42.

In addition to this longitudinal reciprocating action said polishing head also is constructed and arranged to have a reciprocating action in a direction transversely of the belt 140. The transverse reciprocation may be effected in various ways. A suitable such action is indicated here by the use of a vibrating motor 137 which is mounted on the inner side of the platen 42. The reciprocation here will not be of such an extent as to adversely affect the upper mounting structure of the polishing head. There is sufficient leeway in the mounting structure to accommodate the reciprocating action of said motor 137. If a transverse reciprocating action of greater extent is desired, the mounting structure can readily be suitably modified; Thus the work piece will have its surface thoroughly and efficiently polished to an unusual degree of uniformity for a very desirable effect.

With reference to FIGS 5 and 6, a modification of applicants structure is shown in which the basic structure bears substantial similarity to the structure above described, and as a result thereof will here be described with a lesser degree of detail but with the difference being indicated with particularity.

The modified structure comprises an upstanding support ing frame structure 210 similar to the structure 10, and having supporting legs 211 and a pair of opposing parallel vertically disposed plate side members 212 and 213 at upper opposite sides of said frame member. Upstanding from said frame structure 211 and supported thereby is a second frame structure 220 having supporting legs 222 secured to the upper edge portions of said plate members 212 and 213 land in turn supporting a top cover plate 227.

Depending from said plate member 227 is a polishing head assembly or structure 237 describing generally a parallelepiped figure in overall form having integral spaced sides 238 and239. Said side 238 is here shown as an inverted U-shaped plate member having an upper longitudinal side portion 238a and depending leg portions 238k and 238C. Integral with said leg portions adjacent plate member.

the bottom portions is a connecting horizontal plate portion 238d.

Said side portion 239, which is only partially shown, is of identical construction as said side portion 238, and portions thereof will be indicated and referred to in like manner.

Secured to the lower ends respectively of the sides 238a and 239a and of the lower ends of the sides 23811 and 23912 in a suitable manner are plate portions 241 and 242 respectively forming platens and which may be variously formed as to specific shape or surface detail thereof, and are here shown having upwardly turned side portions. The adjacent sides of said platens are spaced apart as indicated in FIG. 5.

Connecting the upper end portions of said side members 238 and 239 and extending outwardly of the ends thereof is a substantially rectangular frame member 244. R- tatably secured to said frame member 244 at each inner corner thereof are jack screws 246 with said jack screws extending upwardly through said plate member 227 threaded through nuts 247 which are integral with said Said jack screws 246 will be mounted in the same manner in connection with the supporting structure as said jack screws 45-48. One of said jack screws 246 will be provided with a crank 246a. Mounted on the shank portions of said jack screws beneath said plate member 227 will be sprockets, and passing thereabout is a sprocket chain 252. This represents conventional design. Thus said jack screw assembly will hold the polishing head assembly in a vertically adjustable suspended position. i

The connective association between the polishing head assembly and the sides 212 and 213 by means of plates 258 and 259 will be by the same rib and groove structure as described in connection with the polishing head assembly 37 and the sides 16 and 17. It is not believed that more detail at this point is necessary.

As previously described, the construction here indicated will provide movement of the polishing head longitudinally of the framework and will also be such as to provide for some movement or play of the polishing head assembly in a direction transversely of the supporting frame structure.

Extending outwardly oppositely of said polishing head assembly at upwardly inclined angles from the lower portions of the sides 238a239a and 238b239b and longitudinally of the frame structure 210 are pairs of arms of different texture or composition for different successive stages in the treatment, finishing or polishing of the surface of a work piece. Carried on the ends of said shafts, as indicated in FIG. 5, are pulleys 272 and 273.

Journaled between said sides 238 and 239 and spaced longitudinally thereof are rollers 274 and 275 respectively carried on shafts 278 and 279 and having secured to an outer end of each shaft as indicated in FIG. are pulleys 281 and 282. Said rollers and their attendant structure are of conventional design. Said belts 269 and 270 will have their other end portions respectively secured to said rollers 274 and 275, with said belts first having passed over the platens 241 and 242. Said rollers 264 and 274 and the rollers 265 and 275 will alternate as take up and supply rollers depending on the direction of travel of the belts. A brake mechanism, such as brake mechanism 70 hereinbefore described, may be embodied in this structure as may be desired in connection with the shafts 266 and 267.

Mounted on the cover plate 227 is a shaft structure 280 identical with said shaft structure 80 and modified only by the addition of pulleys to handle two additional belts. In connection with said shaft are magnetic clutch members 285 identical to clutch members and 95. These are of conventional design. Mounted centrally of said plate member 227 is a reversible electric motor 290 having its driving mechanism in operative association with a gear reduction box 292.

Secured to said shaft will be a plurality of pulleys 295 and said pulley 295 will be used ina collective sense in connection with the belts to be hereinafter indicated. It is not believed at additional views are necessary to show details of structure as the structure is of conventional design and like structure has been shown in detail in connection with the embodiment of the invention first hereinbefore described.

Passing over pulleys 295 and pulleys 272 and 273 respectively are belts 300 and 301. Passing over pulleys 295- land the pulleys 281 and 282 respectively are belts 302 and 303.

Carried on the end portions of arms 260 and 261 respectively are a common design of limit switches 305 and 306 equipped with spring actuating rollers and operative in connection with the polishing belts 269 and 270.

These switches are identical in operation as the switches and 106 previously described.

Mounted on a plate member 310 carried between the legs 211 is an electric motor 312 having a double sprocket 314 carried on its drive shaft 315.

Extending outwardly of said frame structure 210 at either end thereof and supported by braces running to the legs 211 are shelf members 318 and 319 respectively 'having mounted thereon shafts 320 and 321 journaled in bearing brackets 323. Respectively secured to said shafts in alignment with the sprocket 314 are sprockets 325 and 326 with sprocket chain 327 passing over the sprockets 314 and 325. Sprocket chain 328 passes over the sprockets 314 and 326.

Said shaft 320 has a circular plate crank 330' at one end with a crank arm 33i1 connecting it from an off-centered position to one of the arms 261 in a conventional manner. At its other end said crank is constructed having a split end portion with .a pair of spaced circular plate cranks 333 secured to the adjacent ends of said split portion of said shaft with a crank arm 335 pivoted at one end between said cranks 333 at an off center position relative thereto and connecting the same to the other arm 261. Said crank arms are connected to said crank plates at aligned oif center positions.

Said shaft 321 has a crank plate 340 connected at one end thereof having a crank arm 341 connecting it from an off-centered position to one of said arms 260 in a conventional manner. At its other end said shaft identical with said shaft 320 has a split oif portion having a pair of spaced circular cranks 343 secured to the adjacent ends of said split off portion with a crank arm 345 pivoted between said crank plates at an off center position and connecting the same in a conventional manner to the other of said arms 260.

Carried on the inner side portions respectively of said platens 241 and 242 are reciprocating motors 348 and 349, such as vibrating motors, for transverse reciprocation of the polishing head assembly just a sufficient distance so that the grits on the surface of the polishing belts will have no tendency to track or groove the surface of the work piece. It is obvious that it is within the scope of the invention here disclosed to have the polishing head assembly constructed to have two independently hung platens for independent action as compared to the unitary polishing head assembly here indicated.

Positioned to be in an operating relation with said platens 241 and 242 is an endless belt 352 passing over rollers 353 journaled between the extended arms 355 of a supporting plate member 357 over which the top run of said belt passes. Said plate member 357 extends longitudinally of said framework 210 between the legs 211, being secured thereto in a conventional manner, as by bolts. Said plate member and belt will be of sufficient length to handle the work pieces 155 that will be run through the device for polishing.

Extending vertically between the adjacent sides of said belts 269 and 27 0 is an exhaust duct 360 having an intake nozzle 361 substantially the width of said platens 241 and 242 and reducing upwardly to form a cylindrical duct which will be connected to suction apparatus not here shown to draw away and exhaust the dust-like material resulting from the polishing operation.

In operation, applicants modified structure operates essentially in the same manner as that of the structure first hereinabove described. The difiercnces however will be pointed out with some particularity. The polishing head assembly now comprises a pair of depending polishing head portions which are formed by the platens 241 and 242. Two separate polishing belts are mounted for individual action respectively in connection with the platens. These belts are 269 and 270. In the embodiment of the invention here described and illustrated, both polishing belts though carried on separate rollers are driven by a common driving means, which is the shaft 280 and the driving belts in connection therewith. Each of the polishing belts may have a grit or polishing surface of a diflerent character, such as for an initial rough cut with a coarser grit and then a fine polishing efifect or sanding efiect as with aless coarse or a finer grit. A polishing compound may be used in connection with said belts as is taught in connection with the apparatus first above described. It is also within the scope of the invention herein that the polishing heads may be independently mounted rather than both being mounted in a common polishing head assembly as is here shown.

A single motor is here used for reciprocating the polishing head assembly by means of crank plates and arms mounted on the supporting frame structure at either end thereof and being connected with the upwardly inclined arms 260 and 261 so that simultaneously the polishing head assembly is pushed and pulled as it reciprocates. This provides a fast uniform action whether large or small work pieces are being worked upon.

An individual vibrating motor is shown here mounted in connection with each platen. These will provide a rapid movement of short length transversely of the direction of movement of the polishing belts so that none of the :grits of the belts will track on the work pieces, which tracking has a tendency to cause grooves to be cut into work pieces. A single such motor may be used if desired for both platens.

The exhaust member 360' disposed between the platens will carry away the dust-like material resulting from the polishing operation.

The wiring of the apparatus has not been indicated as this will be of conventional design and well known to one familiar with the art. The actual operation of running a work piece through the apparatus will be the same as indicated in the operation first above described.

A modification of applicants platen structure is shown in FIGS. 7-9. In all other respects the structure is identical with what is shown in FIGS. 1-4.

Journaled between legs 1 1 and 14 and the legs 12 and 13 respectively are horizontally aligned vertically spaced pairs of rollers 178 and 17 1 around which the upper run of said belt 140 passes to depress said upper run to space it below the polishing head or platen structure as indicated in FIG. 7. Said supporting member 150 will have its central portion below said platen structure broken away as indicated.

Depending from said platen '42 by side plates 173 and 174 is a platen-175 parallel to said platen 42 and indicated as being integral with said side plates. Said side plates will be secured to said platen 42 in any suitable manner, such as by being bolted thereto, but without any specific fastening means being shown. It is within the scope of this invention that the platen 175 and side plates 173 and 174 will have an'adjustable relation to one another and to the platen 42 to accommodate dilferent sized work pieces. The adjustable relation of said platens and side plates is considered to embody structure well known within the art and as a mechanical expedient. Hence it is not believed that it is necessary to show specific adjusting means relative to the structure here involved.

Said platen 173 has a greater width than said platen 42 as indicated.

Said side plates, as indicated in FIGS. 8 and 9, will extend sufficiently beyond either end of said platen 42 to support adjacent either end thereof transversely spaced pairs of depending angled arms 177 and 178 respectively having journaled therebetween rollers 179 and 180, with said rollers respectively being equipped with cranks 182 and 183 carrying ratchets 185 and 186 and having operatively associated with said ratchets, dogs 185a and 186a being respectively pivoted to the adjacent portions of said arms 177 and 178. s I

An endless polishing belt 190 similar to belt 67 pass over the upwardly facing surface of the platen and over the rollers 179 and whereby said belt as here disclosed will be manually moved endwise and will be locked against movement in operating position by said dogs a and 186s as shown in FIG. 7.

Disposed inwardly of said side plates 173 and 174 respectively are resilient backing strips 192 and 193 being respectively faced on their opposed surfaces with polishing or sanding strips 192a and 193a. As here disclosed, said strips 192 and 193 are stationary and will be changed manually at whatever intervals may be desired. Said strips will be secured to said side plates 173 and 174 in a conventional manner.

In operation, applicants work piece 155 with thus pass between the opposed faces of the platens 42 and 175 whereby both the upper and lower surface of the work piece will be sanded or polished simultaneously. Further the sides of the work piece will also be sanded or polished by the polishing strips 192a and 19311. The resilient backing strips 192 and 193 will have suflicient resilience to accommodate the action of the reciprocating motor 137.

The polishing belt 17 5 may be moved endwise by means of the cranks 182 and 183. For movement of the cranks, the dogs 185a and 186a will be disengaged from the natchets 185 and 186. It is seen in FIG. 7 that the dogs are in opposed relation to :one another whereby there will be no endwise movement of the belt 175 While the apparatus is in operation.

Thus it is seen that the applicant has provided a simply constructed polishing apparatus having the entire polishing mechanism carried on a single supporting member to provide longitudinal as well as transverse reciprocation of the polishing head with a simultaneous moving action of the polishing belt.

It will of course be understood that various changes may be made in the form, details, arrangement and proportions of the parts, without departing from the scope of applicants invention which, generally stated, consists in an apparatus capable of carrying out the objects above set forth, in the parts and combinations of parts disclosed and defined in the appended claims.

What is claimed is:

1. A polishing apparatus having in combination, a polishing head assembly, a supporting frame, means carried by said frame for adjustably holding said polishing head assembly, a pair of spaced polishing heads carried by said assembly, a polishing belt passing over each of said polishing heads, means for respectively supporting said belts, means for moving said belts, means for automatically reversing the direction of travel of said belts, means in association with said assembly for reciprocating said assembly in the direction of travel of said belts, means for reciprocating said assembly transversely of the direction of travel of said belts, and a work supporting means in operative association with said polishing heads.

2. The structure set forth in claim 1, and an exhaust means disposed between said polishing heads.

3. A polishing apparatus having in combination, a polishing head, a supporting frame, means carried by said frame for adjustably carrying said polishing head, means in association with said frame for reciprocating said polishing head longitudinally of said frame, means in association with said polishing head for reciprocating said polishing head transversely of said frame, said polishing head comprising opposed vertically spaced polishing portions, a polishing belt, means for carrying said polishing belt over the upper of said polishing portions, a second polishing belt, and means for overlying the lower of said polishing portions with said second polishing belt, whereby said belts are in opposed adjacent relation to accommodate a work piece therebetween.

4. The structure set forth in claim 3, means comprising opposed polishing portions disposed at either side of said polishing head longitudinally thereof at either side of said vertically spaced polishing portions, and said opposed side polishing portions being formed of a resilient material to accommodate the transverse reciprocation of said polishing head relative to a work piece therebetween.

5. A polishing apparatus having in combination, a polishing head assembly, a supporting framework, means supporting said polishing head assembly in said framework, means reciprocating said polishing head assembly longitudinally and transversely relative to said framework, a platen depending from said polishing head assembly, a polishing belt, means in connection with said first mentioned means supporting said polishing belt to overlie said platen, means moving said polishing belt longitudinally of said framework, means in connection with said first mentioned means carrying work pieces into cooperative association with said platen, and means in connection with said polishing head assembly vertically positioning said platen relative to a work piece.

6. A polishing apparatus having in combination, a supporting frame having work supporting means in connection therewith, a polishing head assembly, means mounting said polishing head assembly within said frame for longitudinal reciprocation thereof, said polishing head comprising a depending platen and longitudinally extended arms, a polishing belt passing over said platen, means carried by said arms moving said belt over said platen, means carried by said polishing head assembly positioning the height of said platen relative to said work sup- 10 porting means, and means carried by said platen transversely reciprocating the same.

7. The structure set forth in claim 6, said polishing head assembly comprising a standard upstanding from said supporting frame, -'a platform carried on said standard, means carried on said platform driving said belt moving means, and vertical adjusting means suspended from said platform carrying said platen for vertical adjustment thereof to position the same relative to a work piece.

8. The structure set forth in claim 7, means carried by said platens reciprocating said platens transversely of said polishing belts.

9. A polishing apparatus having in combination, a polishing head assembly comprising a frame, a plurality of platens depending from said frame, vertical adjusting means carried by said frame suspending said platens, said head assembly having means carrying separate polishing belts respectively passing over said platens, a second frame carrying said first frame for longitudinal movement thereof, means carried by said second frame longitudinally reciprocating said first frame, means integral with said second frame supporting a work piece, and said vertical adjusting means positioning said platens relative to said work piece.

10. A polishing apparatus having in combination, a polishing head, a supporting fnamework, means adjustably suspending said polishing head and said framework, means reciprocating said polishing head longitudinally and transversely of said framework, said polishing head comprising a pair of horizontal vertically spaced polishing belts having opposed polishing portions receiving a work piece therebetween, and means bringing work pieces into engagement with said polishing portions.

References Cited in the file of this patent UNITED STATES PATENTS 2,165,616 Cox July 11, 1939 2,170,792 Brooke Aug. 29, 1939 2,272,651 Woldron et a1 Feb. 10, 1942 2,284,556 Brackett May 26, 1942 2,673,423 Hoyet et al Mar. 30, 1954 2,701,937 Murray Feb. 15, 1955 2,741,880 Falls Apr. 17, 1956 2,843,977 Kuhns July 22, 1958 

1. A POLISHING APPARATUS HAVING IN COMBINATION, A POLISHING HEAD ASSEMBLY, A SUPPORTING FRAME, MEANS CARRIED BY SAID FRAME FOR ADJUSTABLY HOLDING SAID POLISHING HEAD ASSEMBLY, A PAIR OF SPACED POLISHING HEADS CARRIED BY SAID ASSEMBLY, A POLISHING BELT PASSING OVER EACH OF SAID POLISHING HEADS, MEANS FOR RESPECTIVELY SUPPORTING SAID BELTS, MEANS FOR MOVING SAID BELTS, MEANS FOR AUTO- 